A plurality of balances with different types of bearings for their individual elements, e.g. the beam and load carrier, are already known. Thus, in balances with below-balance weighing, bearings are used in the form of knife-edge bearings (German Pat. No. 1,279,946), crossed-band bearings (German Pat. No. 843,606), horizontal taut bands and vertical springs (VDI Zeitschrift, 83/45, 1931, p. 1189). When these types of bearings are used, the pan hangs free and can swing, leading to variations in the measured value. In addition, arrestment and release are required for knife-edge bearings, requiring additional structural material and higher cost. Moreover, knife-edge bearings are subject to wear. Horizontal taut bands require greater pretensioning, resulting in high material stress and preventing placement of considerable loads on the balance.
In top-loading balances the pan is guided by a parallel guidance system in the form of a parallelogram. Once again, knife-edge bearings (German Pat. No. 1,282,307), cross band bearings (Swiss Pat. No. 486,011) and crossed-band bearings (German Pat. No. 2,338,272) are known bearings. The disadvantages of these bearings are the same as those described above, with the crossed-band bearing having a large number of spring elements and therefore a large spring constant, so that hysteresis occurs easily.
Electromagnetic force compensation in beam balances is also a part of the state of the art. The coil can be mounted in the vicinity of the beam pivot, producing a torque to achieve compensation. The coil can also be mounted in the vicinity of the counterweight, producing a force for compensation.
If it is desired to use the bearings described hereinabove and known from the state of the art, in a balance provided with a fixed counterweight on its beam and with a weight changing system on its hook side to expand the weighing range by substitution, one must either take into account the disadvantages of the freely suspended pan or install a parallel guidance system with a number of bearing points subject to a complex stress pattern.